Farmer-led contour ridging can reduce water runoff in African savannahs

Abstract

This article describes an alternative approach to land management using contours which was put into practice on an individual field scale. The main aim of the trial was to conserve rainwater in order to produce an immediate increase in yield. The results apply to the cotton-growing regions of Mali, Burkina Faso, and Northern Côte d'Ivoire where oxen are used for animal traction on gently sloping banks. The climate has a variable rainy season with periods of drought and periods of excess water. The practice involves creating earthen ridges along the contours using an ox-drawn plough. These are maintained with a permanent grass cover. Crops are grown on ridges that follow the contours. The rainwater is kept on the field between the ridges, where it filters into the soil. The excess water drains away slowly to the ends of the field. The additional water infiltration is equivalent to about 10% of the total rainfall. The yield increase is around 30% and higher in dry years. This practice reduces annual yield variations. Managing the land in this way, using the available means on the farm, is inexpensive, so much so that the system is very profitable for farmers. However, external help is needed for marking out the contours. This service is provided by an NGO from Koutiala at a modest price. However, the NGO is unable to meet the demand. The promotion of this method of land management, via farmers associations and NGOs, would help farmers increase their production capacity.